EFFECT OF THE OXIDATIVE POWER OF IODINATION ON THE OPTICAL-PROPERTIES OF ALPACA FIBERS

This study deals with the changes in the optical properties of Alpaca fibres due to the effect of the oxidative power of iodine on the structural characteristics of Alpaca fibres. The diffraction of a He-Ne laser beam was used to measure the dimensional parameters, transverse sectional shape and area of the Alpaca fibre sections. Optical and scanning electron microscopes were used to confirm the geometrical parameters of the cross-sections. Two methods were applied for the measurement of the refractive indices and birefringence of the Alpaca wool fibres. The first was concerned with the application of multiple-beam Fizeau fringes in transmission before treating the fibre with iodine. The second method made use of a double refracting interference microscope (the Pluta polarizing interference microscope). The double beam technique was considered the most suitable in determining the mean refractive indices and the double refraction of the samples after the iodine treatment. Large changes were observed in the values of the refractive indices due to the iodination process, while the birefringence exhibited no appreciable change. Examination of the Alpaca fibres by X-ray diffractometry showed that the crystalline parts had been completely decomposed and degraded due to the effect of I2, which causes oxidative scission of the intermolecular disulphide bonds of the keratins.